In libguestfs ≥ 1.13.26 you can finally use the guestmount --live option.
This option lets you mount the filesystem from a running virtual machine on your host (using FUSE). Reads and writes are handled by a daemon running inside the VM. Writes are permitted and you see guest changes in real time.
By the way, although this is fun, it’s still a bit of a baby-eater, so use with care. At the moment you need identical versions of libguestfs in the guest and host, but we will relax this restriction later.
# guestmount -d FedoraRawhidex64 --live /tmp/mnt # ls /tmp/mnt/tmp # /tmp in the guest foo mallocing-threads glibc-2.14.90-13.i686.rpm mallocing-threads.c glibc-2.14.90-13.src.rpm nscd-2.14.90-13.i686.rpm glibc-2.14.90-13.x86_64.rpm nscd-2.14.90-13.x86_64.rpm glibc-common-2.14.90-13.i686.rpm ssh-ItDNrg1065 glibc-common-2.14.90-13.x86_64.rpm ssh-RXAApq5656 glibc-devel-2.14.90-13.i686.rpm ssh-SfeREo1125 glibc-devel-2.14.90-13.x86_64.rpm ssh-xwLmEq1043 glibc-headers-2.14.90-13.i686.rpm ssh-zZMbMr1430 glibc-headers-2.14.90-13.x86_64.rpm valgrind.txt glibc-static-2.14.90-13.i686.rpm yum_save_tx-2011-10-24-16-250zmRGr.yumtx glibc-static-2.14.90-13.x86_64.rpm yum_save_tx-2011-10-24-16-31IMbTq9.yumtx glibc-utils-2.14.90-13.i686.rpm yum_save_tx-2011-10-24-16-31lPnb8j.yumtx glibc-utils-2.14.90-13.x86_64.rpm yum_save_tx-2011-10-24-16-33F1Fkj_.yumtx
Richard WM Jones 
Do you run any performance tests with this?
I think this will be great for some kind of incremental backups on host machine.
I didn’t, but I bet it’s pretty slow.
Just download guestfish and use the command to mount the live guest right ? Or what else should i do?
Can I mount a running Window Virtual Machine?
thanks for your reply.
You cannot use the
--liveoption for Windows guests, and I wouldn’t advise people to use it unless they know what they are doing because it’s very experimental at present.thank you, but I have another question
should I install libguestfs-live-service package on the Linux guest and modify the XML file or just use the mount command straight ahead.
thank you.
Have a look at the instructions here:
and (quite seriously) make sure you have a backup of the guest because if you do it wrong you can easily end up corrupting the guest.
thanks.